Field of the Invention
The present invention relates to a developer container, a development device, a process cartridge, and an image forming apparatus. In particular, the present invention is preferably applied to a color electro-photographic image forming apparatus.
The electro-photographic image forming apparatus is an image forming apparatus that forms an image on a recording material using an electro-photographic image forming method. Examples of the electro-photographic image forming apparatus include an electro-photographic copying machine, an electro-photographic printer (e.g., laser beam printer, light-emitting diode (LED) printer), a facsimile apparatus, and a word processor.
The process cartridge is a unit having at least an image bearing member. Generally, the process cartridge is a cartridge into which a charging unit, a development unit, or a cleaning unit and the image bearing member are integrated, which is attachable to and detachable from a main body of the image forming apparatus.
Further, the development device is a unit including at least a developer bearing member. Generally, the development device is a unit into which a development unit, a development frame member for supporting the development unit, and relative components are integrated, which is attachable to and detachable from the apparatus main body of the image forming apparatus.
In addition, the developer container is a container for storing developer.
Description of the Related Art
In the image forming apparatus such as a printer employing an electro-photographic image forming method (i.e., electro-photographic process), an electro-photographic photosensitive member (hereinafter, referred to as “photosensitive member”) serving as an image bearing member is electrically charged uniformly. Then, the charged photosensitive member is exposed selectively, so that an electrostatic image is formed on the photosensitive member. Subsequently, the electrostatic image formed on the photosensitive member is visualized as a toner image with toner serving as developer. Then, the toner image formed on the photosensitive member is transferred onto a recording material such as a recording sheet or a plastic sheet, and then heat and pressure are further applied to the toner image transferred onto the recording material, so that the toner image is fixed onto the recording material and the image is recorded thereon.
Generally, maintenance work for various processing units is necessary for the above-described image forming apparatus. In order to easily execute the maintenance work of various processing units, a photosensitive member, a charging unit, a development unit, and a cleaning unit are collectively mounted within a frame member and practically used as a process cartridge that is attachable to and detachable from an image forming apparatus (i.e., apparatus main body). By employing the process cartridge method, it is possible to provide an image forming apparatus excellent in usability.
Such a configuration has been known that the above-described process cartridge includes a cleaning unit having a photosensitive member, a development unit having a development means, and a toner unit for supplying developer.
With respect to a configuration for attaching and detaching the process cartridge (or these units) to and from the apparatus main body, there is provided a method in which the process cartridge is attached to and detached from the apparatus main body in an axis line direction of a photosensitive drum. The process cartridge attached to the apparatus main body is moved upward in a vertical direction, and a position of the process cartridge is fixed when a regulated portion disposed on the process cartridge contacts a regulation portion disposed on the apparatus main body.
In the above-described cartridge method, in order to allow a user to replace a cartridge at proper timing, a function for displaying a number of remaining printable sheets may be added thereto. In order to add such a function, an amount of developer remaining within the cartridge has to be detected or estimated, so that various methods have been provided therefor.
From among the various methods, a light-transmission remaining developer amount detection method has been widely used. In this method, a light path passing through a developer containing chamber is created by a light emitting element such as an LED and a light receiving element such as a phototransistor, and an amount of remaining developer is detected based on a time period during which the light path is blocked by the developer.
In the light-transmission remaining developer amount detection method, as a means for guiding the detection light into the developer containing chamber, a light-emission side light guiding member and a light-reception side light guiding member may be disposed on the developer containing chamber.
The light-emission side light guiding member guides detection light emitted from the light emitting element such as the LED to the inside of the developer containing chamber. The light-reception side light guiding member guides the detection light that has passed through the inside of the developer containing chamber to the light receiving element such as the phototransistor disposed outside the developer containing chamber.
Further, Japanese Patent Application Laid-Open No. 2010-009021 discusses a method in which a light guiding member integrally configured of the light-emission side light guiding member and the light-reception side light guiding member is arranged in a central region in a lengthwise direction of the developer containing chamber.
Further, the development unit may include a developer bearing member for supplying developer to the photosensitive member, a development chamber provided with a developer supply member for supplying the developer to the developer bearing member, and a developer containing chamber for storing the developer to be supplied to the development chamber. In addition, there may be a case where the developer has to be supplied against a gravitational force because the developer containing chamber is positioned below the development chamber in a gravitational direction.
As a method for conveying the developer from the developer containing chamber to the development chamber disposed above the developer containing chamber, there is provided a method in which a flexible sheet member is attached to an agitation member for agitating the developer within the developer containing chamber with the rotational movement of the agitation member. Further, there is provided a development unit having a deformation position and a restoration position. At the deformation position, a sheet member is elastically deformed by making the sheet member abut on a side wall of the developer containing chamber, and at the restoration position, the elastic deformation of the sheet member is released when the developer from the developer containing chamber to the development chamber is conveyed. Thus, the developer is conveyed by a force generated when the sheet member shifts from a deformation state to a restoration state (Japanese Patent Application Laid-Open No. 2011-253203).
However, according to the configuration described in Japanese Patent Application Laid-Open No. 2011-253203, considering the configurations of other components, a recessed portion extending in a lengthwise direction of the developer containing chamber may be provided on a part of the developer containing chamber. When the sheet member moves from the recessed portion to the deformation position, there is a risk that the developer borne on the sheet member may fall off because of misalignment of the contact position between the sheet member and the side wall. As a result, an amount of developer supplied to the development chamber is decreased, and thus there may be an unfavorable effect on image quality.